For a long time, leakage rate prediction models for flange connections have predominantly used gasket stress as the core variable. However, recent experimental studies have revealed an important fact: the variable that forms a one‑to‑one correspondence with leakage rate is not gasket stress, but rather the gasket compression deformation. This finding is rewriting the fundamental logic of flange sealing design and leakage prediction.
The conventional view holds that the higher the gasket stress, the better the sealing effect. But experiments show that under the same gasket stress, leakage rates can differ significantly for gaskets of different materials, thicknesses, or even different batches. The truly decisive variable for leakage rate is the actual deformation amount of the gasket during compression—only when the gasket material undergoes sufficient compressive deformation can it effectively fill the micro‑irregularities of the flange sealing face and block the leakage paths.
This finding has a clear physical mechanism at the microscopic level. No matter how finely machined, flange sealing faces still have roughness peaks and valleys at the micro scale. During compression, the gasket material flows into the microscopic valleys of the sealing face, forming an effective sealing barrier. Research indicates that when gasket deformation is small and insufficient to fill the sealing face valleys, macroscopic leakage channels exist at the contact interface, resulting in higher leakage rates. When deformation increases to eliminate the valley gaps, the interfacial leakage becomes dominated by micro‑capillary leakage channels—there is a distinct transition point and leakage rate difference between the two states.
The leakage rate prediction method based on gasket compression deformation introduces the concept of “conductance” to calculate the leakage rate of flange connections with non‑uniform clamping. Compared with stress‑based models, deformation‑based models offer higher predictive accuracy, particularly when accounting for complex factors such as gasket creep and cyclic plasticity. For commonly used non‑metallic gasket materials such as PTFE and flexible graphite, researchers have established quantitative relationships between gasket compression‑recovery curves and leakage rates through systematic sealing performance tests.
This theoretical advancement has direct practical implications. In the flange design phase, attention should not be focused solely on the stress level of the gasket; whether the gasket can achieve sufficient compression deformation under actual operating conditions is equally important. In gasket selection, gaskets of different materials may deform very differently under the same stress—choosing the appropriate thickness and material to ensure adequate compression deformation under bolt preload is key to sealing reliability. Furthermore, during post‑installation quality checks, measuring the actual compression deformation of the gasket is more indicative of the true sealing state than simply verifying bolt torque.
The paradigm shift from stress‑centric to deformation‑centric analysis represents an important advancement in flange sealing technology. For engineering practices seeking higher sealing reliability, understanding and applying this new analytical framework can help fundamentally improve the design quality and operational safety of flange connections.
All data are sourced from publicly available sources and are provided for learning, communication, and reference purposes only. If there are any errors, please contact for correction. Please make your own judgment, this website assumes no responsibility.